ROME, June 12 (Reuters) - An accord Telecom Italia signed with trade unions Monday night will achieve savings equivalent to 4,500 layoffs through so-called 'solidarity' measures, a source familiar with the matter said on Tuesday.

Solidarity measures usually entail employees cutting their working hours for an equivalent pay reduction.

The source said the measures agreed would affect 30,000 Telecom Italia workers for 12 months.

Presenting Telecom Italia's new business plan in May CEO Amos Genish told unions the phone group needed to cut around 5,000 jobs and would do so through early retirements. (Reporting by Alberto Sisto, writing by Valentina Za, editing by Giulia Segreti)